Tanks for containing liquids are often mounted on a railcar, a semi-trailer, or other vehicle for transporting liquids, often in large volumes. Human access to the tank is provided through a hatchway on a top of the tank. The vertical distance from the hatchway to a bottom wall of the tank can be large enough to require a ladder to safely traverse this distance. The inner chamber of a tank must be accessed, from time to time, for cleaning, inspection and maintenance. Accordingly, the present invention provides a ladder that can be deployed through the hatchway of the tank and secured thereto for safe access and removed upon exit from the tank.